ENERGY DECOMPOSITION ANALYSIS AND NATURAL ORBITAL FOR CHEMICAL VALENCE OF W-E BONDING IN W(CO)4 COMPLEXES WITH TETRYLENE LIGANDS [(CO)4W{NHE}] (E = C – Pb)

Abstract

The natural of W-E bonding in group 14 compounds [(CO)₄W-{NHE}] has been investigated by means of the energy decomposition analysis- natural orbital for chemical valence (EDA-NOCV) method which combines charge (NOCV) and energy (EDA) partitioning schemes at the BP86/TZ2P+  level of theory. The EDA-NOCV indicates that the decrease in bond strength from W4-NHC to W4-NHPb correlates with the decrease of DE_elstat and DE_orb. The EDA-NOCV calculations suggest that the trend of the W-E bond strength was W4-NHC > W4-NHSi > W4-NHGe > W4-NHSn > W4-NHPb. The decrease in the donation (CO)₄W¬ NHE, which is manifested in the calculated values for DE_s and in the electrostatic attraction, DE_elstat , provides a rationale for the weaker bonding of the heavier atoms E. The bonding in the complexes with N-heterocyclic carbene and analogues W4-NHE exhibits the typical feature in terms of strong s-donation and weak p-donation.